Video format determination device, video format determination method, and video display device

ABSTRACT

There is provided a video format determination device including a video input unit that receives video having a feature amount for each pixel, a region representative value calculation unit that divides a left-eye video region and a right-eye video region in a three-dimensional video format to be determined in input video into small regions, and then computes representative values of feature amounts of the respective small regions for each of the left-eye video region and the right-eye video region, a correction value calculation unit that calculates a correction value to correct the representative values, a data correction unit that corrects the representative values, an inter-region correlation calculation unit that calculates the correlation between the left- and right-eye video regions, and an evaluation determination unit that evaluates the correlation to determine whether input video is in the three-dimensional video format.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 13/875,817, filed May 2, 2013, which claims thebenefit of priority from prior Japanese Application No. 2012-111815,filed May 15, 2012, the entire content of which is hereby incorporatedby reference

BACKGROUND

The technology disclosed in the present specification relates to a videoformat determination device and a video format determination method thatare used to determine the format of a video signal, and a video displaydevice that switches display modes of a video signal based on a formatdetermination result, and more particularly, to a video formatdetermination device, a video format determination method, and a videodisplay device that realize reliable determination of athree-dimensional video format or two-dimensional video format with asmall calculation amount.

A viewer can be presented with a stereoscopic video that can bethree-dimensionally seen by displaying a video using parallax betweenright and left eyes. For example, a time-division stereoscopic videodisplay system includes a combination of a display device that displaysa plurality of different videos in a time-division manner and eyeglassesthat video viewers wear. The display device alternately displaysleft-eye images and right-eye images having parallax at very short timeintervals. In addition, while a left-eye video is displayed, the lefteye part of the eyeglasses transmits light, and the right eye partthereof is shielded from light. On the other hand, while a right-eyevideo is displayed, the right eye part of the eyeglasses transmitslight, and the left eye part is shielded from light. In addition, in aspace-division stereoscopic video display system, a left-eye video and aright-eye video are multiplexed and displayed on one screen, and theleft eye part of eyeglasses that a viewer wears only transmits light ofthe left-eye video, and the right eye part thereof only transmits lightof the right-eye video. In both systems, the brain of a user who viewsthe video fuses the left-eye video and the right-eye video so as torecognize the fusion as a stereoscopic video.

As transmission formats of three-dimensional video signals, for example,three types of a side-by-side format, a top-and-bottom format, and aframe sequential format can be exemplified. In the side-by-side format,active regions of two-dimensional video signals are divided into twohalves in the horizontal direction as shown in FIG. 23, and a(concurrent) left-eye video L and a right-eye video R are multiplexed tothe left and right sides, that is, in the horizontal direction. Inaddition, in the top-and-bottom format, active regions oftwo-dimensional video signals are divided into two halves in thevertical direction as shown in FIG. 24, and a (concurrent) left-eyevideo L and right-eye video R are multiplexed to the upper and lowersides, that is, in the vertical direction. In the frame sequentialformat, left-eye videos L and right-eye videos R are alternatelyinserted on a time axis as shown in FIG. 25.

Any of the transmission formats controls a display device that processesvideo signals such that left-eye videos and right-eye videos areseparated from the signals, correctly arranged on the time axis, andthereby the left-eye videos are displayed for the left eye and theright-eye videos are displayed for the right eye. In this case, it is ofcourse necessary to switch a display format by determining whether ornot the video signal currently transmitted is for three-dimensionalvideos, and if the signal is for three-dimensional videos, determiningin what transmission format shown in any of FIGS. 23 to 25 describedabove the signal is.

If a signal indicating a transmission format is added to transmittedvideo data, the determination can be accurately made. However, there aresome broadcasting signals and DVDs (Digital Versatile Discs) to whichsuch a signal is not added. In addition, there is content of whichsignals have different transmission formats, such as two-dimensionalvideo content of a TV commercial, and three-dimensional video content ofa TV program. Manually switching display modes every time signals areswitched is very inconvenient for a viewer. If a display mode for whicha video format is wrong is selected, an inconvenient incident in whichtwo different types of images are displayed overlappingly occurs.

There are several proposals for devices that determine a video formatfrom correlation of regions respectively corresponding to a left-eyevideo and a right-eye video in an image. For example, a proposal for avideo display device that switches a display format by obtaining aposition histogram from difference values in units of pixels tocalculate correlation, and determining whether or not the result is forthree-dimensional video has been made (for example, refer to JapaneseUnexamined Patent Application Publication No. 2010-68309). In addition,another proposal for a stereoscopic image format determination devicethat automatically determines a format from the inner product of featureamounts of each region of a left-eye video and a right-eye video hasbeen made (refer to Japanese Unexamined Patent Application PublicationNo. 2006-332985).

In the method for determining a format having the correlation betweenrespective left- and right-eye video regions in a video signal as anindex, determination of whether data is for three-dimensional video ortwo-dimensional video is made by obtaining predetermined feature amountsfrom the video regions and having a cumulative result of the absolutedifference value between the feature amounts as estimation values.Herein, when an evaluation value is small, the correlation between theleft- and right-eye video regions is high, and thus it can be determinedthat the respective regions are in the relationship of correspondingleft and right videos, in other words, data is for three-dimensionalvideo. Conversely, when an evaluation value is large, the correlationbetween the left- and right-eye video regions is low, and thus it can bedetermined that the respective regions are not in the relationship ofcorresponding left and right videos, and the data is for two-dimensionalvideo.

However, if evaluation is performed merely based on the calculation ofthe correlation between left- and right-eye video regions, there areproblems in terms of performance in that determination accuracy is low,and reliability is hard to guarantee.

For example, since there is parallax between a left video and a rightvideo in a stereoscopic video, the correlation between the videos is lowwhen the parallax is large, and thus there is a possibility of makingerroneous determination that the video is not a three-dimensional video.FIG. 26 shows a result of an absolute difference value ABS (Lch-Rch) offeature amounts by simply matching the feature amounts of a left-eyevideo (Lch) and a right-eye video (Rch) having parallax. As shown in thedrawing, when parallax is large, a difference is generated betweenvideos, accordingly the correlation is low, and as a result, there is apossibility of making erroneous determination that the video is atwo-dimensional video.

In addition, there is a possibility of making erroneous determinationthat a video is not a three-dimensional video due to a difference otherthan parallax between left and right videos. There is no problem in a CG(Computer Graphics) video, or the like, but particularly in the case ofa three-dimensional video photographed using a twin lens camera,luminance, contrast, γ, color, bands of video signals, a noise amount,and the like may be significantly different between left and rightvideos due to differences in characteristics, differences ininstallation accuracy of lens systems, and the like. FIG. 27 shows aresult of an absolute difference value ABS (Lch-Rch) of a feature amountby simply matching the feature amounts of a left-eye video (Lch) and aright-eye video (Rch) showing differences in luminance and contrast. Asshown in the drawing, the difference is further made between videos whenthe differences in luminance and contrast are great, the correlationthereof becomes low, and thus a possibility of making erroneousdetermination that the videos are two-dimensional videos continuouslyincreases.

Conversely, there are also cases in which a two-dimensional video iserroneously determined to be a three-dimensional video if videos havinga high correlation between regions respectively corresponding to aleft-eye video and a right-eye video are included therein. FIG. 28 showsan image of a seascape as an example of an image showing an insufficientchange in luminance and contrast, and since the difference in thefeature amounts on the left and right sides of the image is small and ahigh correlation is shown, there is a possibility of the image beingerroneously determined as a three-dimensional video in the side-by-sideformat.

In addition, during determination of a video format, the evaluationmethod merely using calculation of the correlation between left- andright-eye video regions includes calculation in units of pixels andcalculation of an inner product, which causes a large calculationamount, and therefore the amount adversely affects fast determinationand costs.

SUMMARY

It is desirable for the technology disclosed in the presentspecification to provide excellent video format determination device,video format determination method, and video display device that canreliably realize determination of a three-dimensional video format or atwo-dimensional video format with a small calculation amount.

According to an embodiment of the present disclosure, there is provideda video format determination device including a video input unit thatreceives video having a feature amount for each pixel, a regionrepresentative value calculation unit that divides a left-eye videoregion and a right-eye video region in a three-dimensional video formatto be determined in input video into small regions having M rows and Ncolumns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, a correction valuecalculation unit that calculates a correction value to correct therepresentative values based on an average value of feature amounts ofthe left-eye video region and an average value of feature amounts of theright-eye video region, a data correction unit that corrects therepresentative values of the respective small regions computed for oneof the left-eye video region and the right-eye video regions using thecorrection value, an inter-region correlation calculation unit thatcalculates the correlation between the left- and right-eye video regionsby cumulatively adding differences of the representative values ofcorresponding small regions in the left-eye video region and theright-eye video region, and an evaluation determination unit thatevaluates the correlation between the left- and right-eye video regionsto determine whether input video is in the three-dimensional videoformat.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination device including a video inputunit that receives video having a feature amount for each pixel, aregion representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, an inter-region correlationcalculation unit that calculates the correlation between the left- andright-eye video regions by cumulatively adding differences of therepresentative values of corresponding small regions in the left-eyevideo region and the right-eye video region, an intra-region correlationcalculation unit that calculates the correlation within at least oneregion of the left-eye video region and the right-eye video region, andan evaluation determination unit that calculates an evaluation valuebased on a ratio of the correlation between the left- and right-eyevideo regions to the correlation within the region to determine whetherinput video is in the three-dimensional video format based on theevaluation value.

The region representative value calculation unit may use a luminancesignal of each pixel as a feature amount.

The inter-region correlation calculation unit may calculate thecorrelation between the left- and right-eye video regions based on thedifferences of the representative values of corresponding small regionsin the left-eye video region and the right-eye video region.

The inter-region correlation calculation unit may calculate thecorrelation between the left- and right-eye video regions by performingcumulative weighted addition of the differences of the representativevalues of corresponding small regions between the left-eye video regionand the right-eye video region.

The inter-region correlation calculation unit may perform the cumulativeweighted addition using a weighting function that suppresses addition ofa difference whose value is equal to or lower than a predeterminedvalue.

The video format determination device may further include anintra-region correlation calculation unit that calculates thecorrelation within at least one region of the left-eye video region andthe right-eye video region. The evaluation determination unit maycalculate an evaluation value based on a ratio of the correlationbetween the left- and right-eye video regions to the correlation withinthe region to determine whether input video is in the three-dimensionalvideo format based on the evaluation value.

The evaluation determination unit may defer determination of a videoformat of input video when the correlation within the region has a valueequal to or lower than a predetermined threshold value.

The region representative value calculation unit may dispose theleft-eye video region and the right-eye video region on left and rightof the input video, respectively, and computes representative values ofthe respective small regions in a determination mode to determinewhether or not the input video is three-dimensional video in aside-by-side format.

The region representative value calculation unit may dispose theleft-eye video region and the right-eye video region on top and bottomof the input video, respectively, and computes representative values ofthe respective small regions in a determination mode to determinewhether or not the input video is three-dimensional video in atop-and-bottom format.

A plurality of determination modes in which a video format is determinedwith regard to each of a plurality of three-dimensional video formatsmay be provided. And when input video is determined not to bethree-dimensional video in a certain determination mode, the evaluationdetermination unit may determine whether or not the input video isthree-dimensional video by switching to another determination mode.

During determination of a video format of a moving image, the evaluationdetermination unit may decide whether or not a determination state of avideo format should be transitioned based on a determination result of avideo format for a current frame, a determination state of a videoformat for the previous frame, and a time elapsed from a change in thedetermination result.

The evaluation determination unit may set a threshold value to be usedin determining an evaluation value according to a determination state ofa video format.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination device including a video inputunit that receives video having a feature amount for each pixel, aregion representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, a representative valueranking calculation unit that calculates rankings of the small regionsfor each row and each column based on the computed representative valuesin each of the left-eye video region and the right-eye video region, andan evaluation determination unit that evaluates a degree of similarityof rankings of corresponding small regions between the left-eye videoregion and the right-eye video region to determine whether or not theinput video is in the three-dimensional video format.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination device including a video inputunit that receives video having a feature amount for each pixel, aregion representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, a representative valuedirection calculation unit that calculates directions in which therepresentative values change in each of the small regions in each of theleft-eye video region and the right-eye video region, and an evaluationdetermination unit that further evaluates a degree of similarity ofdirections in which the representative values change in correspondingsmall regions in the left-eye video region and the right-eye videoregion to determine whether or not the input video is in thethree-dimensional video format.

By multiplying a weighting filter coefficient of n×m by each of n×msmall regions in each of the left-eye video region and the right-eyevideo region, the representative value direction calculation unit maycalculate the directions in which the representative values change ineach of the small regions.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination method including receiving videohaving a feature amount for each pixel, dividing a left-eye video regionand a right-eye video region in a three-dimensional video format to bedetermined in input video into small regions having M rows and Ncolumns, respectively, and then computing representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, calculating a correctionvalue to correct the representative values based on an average value offeature amounts of the left-eye video region and an average value offeature amounts of the right-eye video region, correcting therepresentative values of the respective small regions computed for oneof the left-eye video region and the right-eye video regions using thecorrection value, calculating the correlation between the left- andright-eye video regions by cumulatively adding differences of therepresentative values of corresponding small regions in the left-eyevideo region and the right-eye video region, and evaluating thecorrelation between the left- and right-eye video regions to determinewhether input video is in the three-dimensional video format.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination method including receiving videohaving a feature amount for each pixel, dividing a left-eye video regionand a right-eye video region in a three-dimensional video format to bedetermined in input video into small regions having M rows and Ncolumns, respectively, and then computing representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, calculating the correlationbetween the left- and right-eye video regions by cumulatively addingdifferences of the representative values of corresponding small regionsin the left-eye video region and the right-eye video region, calculatingthe correlation within at least one region of the left-eye video regionand the right-eye video region, and calculating an evaluation valuebased on a ratio of the correlation between the left- and right-eyevideo regions to the correlation within the region to determine whetherinput video is in the three-dimensional video format based on theevaluation value.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination method including receiving videohaving a feature amount for each pixel, dividing a left-eye video regionand a right-eye video region in a three-dimensional video format to bedetermined in input video into small regions having M rows and Ncolumns, respectively, and then computing representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, calculating rankings of thesmall regions for each row and each column based on the computedrepresentative values in each of the left-eye video region and theright-eye video region, and evaluating a degree of similarity ofrankings of corresponding small regions between the left-eye videoregion and the right-eye video region to determine whether or not theinput video is in the three-dimensional video format.

Further, according to an embodiment of the present disclosure, there isprovided a video format determination method including receiving videohaving a feature amount for each pixel, dividing a left-eye video regionand a right-eye video region in a three-dimensional video format to bedetermined in input video into small regions having M rows and Ncolumns, respectively, and then computing representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, calculating directions inwhich the representative values change in each of the small regions ineach of the left-eye video region and the right-eye video region, andevaluating a degree of similarity of directions in which therepresentative values change in corresponding small regions in theleft-eye video region and the right-eye video region to determinewhether or not the input video is in the three-dimensional video format.

Further, according to an embodiment of the present disclosure, there isprovided a display device including an input unit that receives videosignals, a video signal processing unit that determines the format ofinput video signals, and performs processing of a three-dimensionalvideo signal or a two-dimensional video signal by switching displayformats according to the determination result, and a display unit thatdisplays video signals that have been processed in the video signalprocessing unit on a screen. The video signal processing unit divides aleft-eye video region and a right-eye video region in athree-dimensional video format to be determined in input video intosmall regions having M rows and N columns, respectively, and thencomputes representative values of feature amounts of the respectivesmall regions for each of the left-eye video region and the right-eyevideo region, calculates a correction value to correct therepresentative values based on an average value of feature amounts ofthe left-eye video region and an average value of feature amounts of theright-eye video region, calculates a correction value to correct therepresentative values based on an average value of feature amounts ofthe left-eye video region and an average value of feature amounts of theright-eye video region using the correction value, calculates thecorrelation between the left- and right-eye video regions bycumulatively adding differences of the representative values ofcorresponding small regions in the left-eye video region and theright-eye video region, and evaluates the correlation between the left-and right-eye video regions to determine whether input video is in thethree-dimensional video format.

According to the technology disclosed in the present specification, itis possible to provide an excellent video format determination device,video format determination method, and video display device that canreliably realize determination of a three-dimensional video format or atwo-dimensional video format with a small calculation amount, and is notinfluenced by various kinds of capturing methods and video content.

Other objects, characteristics, and advantages of the technologydisclosed in the present specification may be clarified by furtherdetailed description with reference to embodiments to be described belowand the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an internal configuration of a video formatdetermination device 100 installed inside a video signal processing unit2001;

FIG. 2 is a diagram showing an example in which an input video isdivided in a determination mode for determining a three-dimensionalvideo format in the side-by-side format;

FIG. 3 is a diagram showing an example in which an input video isdivided in a determination mode for determining a three-dimensionalvideo format in the top-and-bottom format;

FIG. 4 is a diagram exemplifying another method for dividing an inputvideo;

FIG. 5 is a diagram exemplifying another method for dividing an inputvideo;

FIG. 6 is a diagram showing an example of a weighting function used incumulative difference calculation;

FIG. 7 is a flowchart showing a process of a determination unit 180 fordetermining a video format of an input video based on an evaluationvalue Z;

FIG. 8 is a diagram showing a determination processing method of a videoformat based on the evaluation value Z;

FIG. 9 is a flowchart showing a process of the determination unit 180for determining a plurality of video formats based on the evaluationvalue Z;

FIG. 10 is a state transition diagram used in operation control duringvideo format determination of a moving image by the video formatdetermination device 100;

FIG. 11 is a flowchart showing a process for determining whether or nottransition should be performed between states in the state transitiondiagram shown in FIG. 10;

FIG. 12 is a diagram showing another configuration example of a videoformat determination device 1200;

FIG. 13 is a diagram exemplifying a three-dimensional video in theside-by-side format;

FIG. 14 is a diagram showing results obtained by calculatingrepresentative values of each small region in an input image shown inFIG. 13;

FIG. 15 is a diagram showing results obtained by calculating ranking ofluminance in the calculation results of the representative values ofeach small region shown in FIG. 14;

FIG. 16 is a diagram showing eight masks used in template matching ofPrewitt;

FIG. 17 is a diagram showing results of directions of luminance changesin each small region obtained by applying the template matching ofPrewitt to the calculation result of the representative values of thesmall regions shown in FIG. 14;

FIG. 18 is a diagram showing evaluation results for the results ofranking of luminance shown in FIG. 15;

FIG. 19 is a diagram showing evaluation results for the calculationresults of the directions of luminance changes shown in FIG. 17;

FIG. 20 is a diagram schematically showing a configuration example of avideo display system to which the technology disclosed in the presentspecification can be applied;

FIG. 21 is a diagram showing a control operation of right and leftshutter lenses 2101, 2102 of shutter glasses 2100 that are synchronizedwith a display period of a left-eye video image L of a display device2000;

FIG. 22 is a diagram showing a control operation of the right and leftshutter lenses 2101, 2102 of the shutter glasses 2100 that aresynchronized with a display period of a right-eye video image R of thedisplay device 2000;

FIG. 23 is a diagram showing a three-dimensional video format in theside-by-side format;

FIG. 24 is a diagram showing a three-dimensional video format in thetop-and-bottom format;

FIG. 25 is a diagram showing a three-dimensional video format in theframe sequential format;

FIG. 26 is a diagram exemplifying a case in which a stereo video havingparallax between left and right videos is erroneously determined as atwo-dimensional video;

FIG. 27 is a diagram exemplifying a case in which a three-dimensionalvideo is erroneously determined as a two-dimensional video due to thedifference in luminance and contrast of left and right videos; and

FIG. 28 is a diagram exemplifying a case in which a two-dimensionalvideo having a high correlation between the right and left sides iserroneously determined as a three-dimensional video in the side-by-sideformat.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

FIG. 20 schematically shows a configuration example of a video displaysystem to which the technology disclosed in the present specificationcan be applied. The video display system shown in the drawing includes acombination of a display device 2000 for three-dimensional display(stereoscopic vision) and shutter glasses 2100 equipped with shuttermechanisms in each of a left eye part and a right eye part. Hereinafter,a liquid crystal display (LCD) will be used as the display device 2000to display three-dimensional images. However, the gist of the technologydisclosed in the present specification is not necessarily limited to aliquid crystal display.

The display device 2000 alternately displays left-eye videos L andright-eye videos R in a time division manner. On the other hand, theshutter glasses 2100 are synchronized with switching timings of theleft-eye videos L and the right-eye videos R on the display device 2000side so as to perform switching to opening and closing of left and rightshutter lenses 2101 and 2102. In communication between the displaydevice 2000 and the shutter glasses 2100, a wireless network using radiowave communication such as Wi-Fi, IEEE802.15.4, or the like is used sothat packets in which information necessary for controlling opening andclosing timings of the left and right shutter lenses 2101 and 2102 isdescribed are transmitted from the display device 2000 to the shutterglasses 2100. Of course, infrared communication or communication methodsother than the wireless network can be applied thereto.

The display device 2000 includes a video signal processing unit 2001, atiming control unit 2002, a gate driver 2003, a data driver 2004, aliquid crystal display panel 2005, and a communication unit 2007.

The liquid crystal display panel 2005 includes a liquid crystal layerand transparent electrodes which face each other with the liquid crystallayer interposed therebetween, color filters, and the like (none ofwhich is shown). In addition, on the back side of the liquid crystaldisplay panel 2005, a backlight (surface light source) 2006 is disposed.The backlight 2006 includes LEDs (Light Emitting Diodes), and the likehaving satisfactory persistence characteristics.

In the video signal processing unit 2001, an image quality correctionprocess for enhancing sharpness of video images and improving contrastis performed.

In addition, in the video signal processing unit 2001, a video formatdetermination device to be described later is installed so as to switchdisplay formats of input video signals based on a determination resultof a video format. In other words, it is determined whether an inputvideo signal is a two-dimensional video signal or a three-dimensionalvideo signal, and when the signal is a three-dimensional video signal,the format thereof is determined. Then, when the input signal isdetermined to be a three-dimensional video signal, the signal isseparated into left-eye video images L and right-eye video images R, andcorrectly arranged along the time axis, and left and right video signalsare output in order to alternately display the left-eye video images Land the right-eye video images R on the liquid crystal display panel2005 in a time division manner.

Left-eye video signals and right-eye video signals which are convertedin the video signal processing unit 2001 are input to the timing controlunit 2002. The timing control unit 2002 converts the input left-eyevideo signals and right-eye video signals into signals to be input tothe liquid crystal display panel 2005, and generates pulse signals usedto cause a panel driving circuit that includes the gate driver 2003 andthe data driver 2004 to operate.

The gate driver 2003 is a drive circuit that generates signals forsequential driving, and outputs a driving voltage to gate bus linesconnected to each pixel in a display panel 134 according to signalstransmitted from the timing control unit 2002. In addition, the datadriver 2004 is a drive circuit that outputs driving voltages based onvideo signals, and generates and outputs signals applied to data linesbased on signals transmitted from the timing control unit 2002.

In addition, in order to compensate for response speed of the liquidcrystal display panel 2005, over-driving is appropriately performed.Over-driving is a process for improving response characteristics of thepanel by applying a driving voltage equal to or higher than a targetvoltage of the panel drive circuit to liquid crystal elements so as toquickly reach the target voltage.

The communication unit 2007 operates as an access point in the wirelessnetwork such as Wi-Fi, or IEEE802.15.4, and includes one or more shutterglasses 2100 operating as terminals in its own basic service set (BSS).The communication unit 2007 transmits packets in which informationnecessary for controlling opening and closing timings of the left andright shutter lenses 2101 and 2102 on the shutter glasses 2100 side isdescribed.

FIG. 21 shows a control operation of the left and right shutter lenses2101 and 2102 of the shutter glasses 2100 that are synchronized with adisplay period of a left-eye video image L of the display device 2000.As shown in the drawing, during the display period of the left-eye videoimage L, the left shutter lens 2101 is set to be in an open state andthe right shutter lens 2102 to be in a closed state according tosynchronization packets wirelessly transmitted from the display device2000 side, and display light LL based on the left-eye video image Lreaches the left eye of a user.

In addition, FIG. 22 shows a control operation of the left and rightshutter lenses 2101 and 2102 of the shutter glasses 2100 that aresynchronized with a display period of a right-eye video image R. Asshown in the drawing, during the display period of the right-eye videoimage R, the right shutter lens 2102 is set to be in an open state andthe left shutter lens 2101 to be in a closed state, and display light RRbased on the right-eye video image R reaches the right eye of the user.

The display device 2000 alternately displays the left-eye video image Land the right-eye video image R on the liquid crystal display panel 2005by each field in a time division manner. On the shutter glasses 2100side, the left and right shutter lenses 2101 and 2102 are synchronizedwith switching of video images of each field of the display device 2000and alternately perform opening and closing operations. The brain of theuser who observes displayed images through the shutter glasses 2100fuses the left-eye video images L and the right-eye video images R andthereby three-dimensionally recognizes the video images displayed on thedisplay device 2000.

Note that the technology disclosed in the present specification can beapplied not only to the three-dimensional video display format usingactive glasses such as the shutter glasses 2100 as described above butalso to a three-dimensional video display format for the naked eye andto a three-dimensional video display format using passive glasses.

FIG. 1 shows an internal configuration of a video format determinationdevice 100 installed inside the video signal processing unit 2001. Thevideo format determination device 100 shown in the drawing receives avideo signal, selects a side-by-side determination mode or atop-and-bottom determination mode according to determination mode, andobtains a determination result D.

Herein, the video signal input to the video format determination device100 is assumed to be a video signal having resolution of, for example,an HD (High Definition) signal of 60 Hz having a pixel size of1920×1080, an SD (Standard Definition) signal having a pixel size of720×480, or a still image signal recorded by a digital camera. FIG. 1shows a configuration example in which a process for determining a videoformat for one frame of a still image is performed, but in the case of avideo signal, a video format can be determined by processing one frameout of a moving image of which frames are consecutively input.

The video format determination device 100 includes a feature amountcalculation unit 110, a region representative value calculation unit120, a correction value calculation unit 130, a data correction unit140, a cumulative difference value calculation unit 150, an intra-regioncorrelation calculation unit 160, an evaluation value calculation unit170 and a determination unit 180.

The feature amount calculation unit 110 calculates a feature amount whena video format is determined based on an input video signal. Tocalculate the feature amount, a method of excluding high-frequencyinformation using a low-frequency pass filter, and a method of acquiringedge information using a band-pass filter or slope calculation based onthe differences between adjacent pixels are considered, but any methodmay be used. In addition, particularly, a luminance value of input videomay be used as it is without calculating a feature amount. Hereinbelow,a luminance value of input video is set to be used as a feature amountas it is.

The region representative value calculation unit 120 divides a left-eyevideo region and a right-eye video region in a video frame respectivelyinto a plurality of small regions according to determination modes (inother words, according to a three-dimensional video format to bedetermined), and then computes a representative value of feature amountscalculated by the feature amount calculation unit 110 for each smallregion. Herein, as a representative value, an average value of featureamounts (luminance values) of each region is calculated. Whichthree-dimensional video format should be determined is instructedautomatically or manually by a user from, for example, the outside ofthe video format determination device 100.

When the determination mode in which the side-by-side three-dimensionalvideo format is determined is set, for example, the regionrepresentative value calculation unit 120 divides the input video intotwo halves on the left and right sides, and then divides respective leftand right regions into M×N small regions, in other words, into 2M×Nsmall regions in total as shown in FIG. 2.

Next, the region representative value calculation unit 120 computes anaverage value from feature amounts of each of the small regions as, forexample, a representative value of the small regions. The average valueof small regions L(p, q) and R(p, q) on the respective left and rightsides shown in FIGS. 2 and 3 can be calculated as shown in the followingformulas (1) and (2).

$\begin{matrix}{{L\left( {p,q} \right)} = {\frac{1}{P \times Q}{\sum\limits_{x = {({p \times P})}}^{P - 1}\; {\sum\limits_{y = {({q \times Q})}}^{Q - 1}\; {F\left( {x,y} \right)}}}}} & (1) \\{{R\left( {p,q} \right)} = {\frac{1}{P \times Q}{\sum\limits_{x = {{({p \times P})} + {({M \times P})}}}^{P - 1}\; {\sum\limits_{y = {({q \times Q})}}^{Q - 1}\; {F\left( {x,y} \right)}}}}} & (2)\end{matrix}$

Wherein, each of the variables in the above formulas (1) and (2) isdefined as follows.

L(p, q): A representative value of the small regions for a left-eyevideo image

R(p, q): A representative value of the small regions for a right-eyevideo image

F(x, y): A feature amount (luminance value) in a unit of a pixel ofinput video

x: A horizontal pixel position of input video, y: A vertical pixelposition of input video

X: The number of horizontal pixels of F(x, y), Y: The number of verticallines of F(x, y)

M: The number of divided regions of respective left and right videoregions in the horizontal direction

N: The number of divided regions of respective left and right videoregions in the vertical direction

P: The number of horizontal pixels in each of the divided regions(P=X/M)

Q: The number of vertical pixels in each of the divided regions (Q=Y/N)

p: A horizontal pixel position in a unit of a small region, q: Avertical pixel position in a unit of a small region

In addition, when a determination mode in which the top-and-bottomthree-dimensional video format is determined is set, the regionrepresentative value calculation unit 120 divides input video into twohalves on the upper and lower sides, and then divides the respectiveupper and lower regions into M×N small regions, in other words, intoM×2N small regions in total as shown in FIG. 3. Then, the regionrepresentative value calculation unit 120 computes an average value fromfeature amounts of the small regions as, for example, the representativevalue of the small regions.

Note that, as methods for dividing input video, a method in whichcontracted regions of blocks obtained by dividing a left-eye videoregion and a right-eye video region so as to respectively have M rowsand N columns are used (refer to FIG. 4), and a method in which anoverlapping region with adjacent blocks is used (refer to FIG. 5) areexemplified, in addition to the method in which the regions are clearlydivided into blocks as shown in FIGS. 2 and 3.

In addition, the number of divisions within the range not affected byparallax is also a characteristic of the technology disclosed in thepresent specification. In other words, in the examples shown in FIGS. 2and 3, the number of M×N divisions is set to 4×4 divisions for each ofthe left-eye video region and the right-eye video region, but asufficiently rough number such as 16×16 divisions, 12×12 divisions, or8×8 divisions is another characteristic thereof. A number of divisionsthat is asymmetric in the horizontal direction and the verticaldirection such as 16×8 divisions may be used. In this manner, by using asufficiently rough number of divisions for input video, the influence ofnoise or bands of video signals as well as the influence of parallax canbe eliminated, and at the same time, a calculation amount can bereduced.

The correction value calculation unit 130 calculates, for a featureamount of input resolution supplied from the feature amount calculationunit 110, average values APL_L and APL_R of feature amounts (luminancevalues) of each of the left and right video regions respectively asrepresentative values of the regions as shown in the following formulas(3) and (4), separate from the calculation of the representative valuefor the small regions in the region representative value calculationunit 120.

$\begin{matrix}{{APL\_ L} = {\frac{1}{{X/2} \times Y}{\sum\limits_{x = 0}^{{X/2} - 1}\; {\sum\limits_{y = 0}^{Y - 1}\; {F\left( {x,y} \right)}}}}} & (3) \\{{APL\_ R} = {\frac{1}{{X/2} \times Y}{\sum\limits_{x = {X/2}}^{X - 1}\; {\sum\limits_{y = 0}^{Y - 1}\; {F\left( {x,y} \right)}}}}} & (4)\end{matrix}$

Then, the difference between the calculated values APL_L and APL_R iscomputed as a correction value a shown in the following formula (5), andsupplied to the data correction unit 140 in the latter stage.

α=APL_L−APL_R  (5)

When the representative value L(p, q) of each small region in theleft-eye video region is acquired from the region representative valuecalculation unit 120, the data correction unit 140 corrects the valueaccording to the following formula (6) using the correction value asupplied from the correction value calculation unit 130, and thenacquires a representative value L′(p, q) after correction.

L′(p,q)=L(p,q)−α  (6)

With an operation of the representative values shown in the aboveformula (6), the influence of luminance, contrast, and γ (differencesbetween the left and right video regions attributable to the differencesof characteristics of left and right cameras) can be eliminated forthree-dimensional video acquired using a twin lens camera.

The cumulative difference value calculation unit 150 obtains acumulative sum S obtained by weighting the difference of therepresentative values of the corresponding small regions between theleft- and right-eye video regions. However, as the representative valueof each small region on the left-eye video region side, the correctionvalue L′(p, q) obtained in the data correction unit 140 is used. Thecumulative sum S can be calculated according to the following formula(7), and the sum serves as a correlation value S between the left-eyeand right-eye video regions in the video.

$\begin{matrix}{S = {\sum\limits_{p = 0}^{M - 1}\; {\sum\limits_{q = 0}^{N - 1}\; {W\left( {{L^{\prime}\left( {p,q} \right)} - {R\left( {p,q} \right)}} \right)}}}} & (7)\end{matrix}$

Note that, as a weight W (in the above formula (7)) given to thedifference of representative values of corresponding small regions ofthe left- and right-eye video regions, a weighting function thatsuppresses addition of a difference that is equal to or lower than apredetermined value is used. Specifically, a weighting function as shownin FIG. 6 and the following formula (8) can be used. The weightingfunction W shown in the drawing is placed with an extremely small weightfor an input x that is equal to or lower than a predetermined value c.Thus, when a difference value L′(p, q)−R(p, q) used as the input xdecreases as the value is affected by parallax, luminance, and noisecaused by photographing using a twin lens camera, addition to acorrelation value S is suppressed. As a result, effects of eliminatingthe influence of parallax and the like and increasing determinationaccuracy of a three-dimensional video format can be further expectedthan when a correlation value is calculated simply as an absolutedifference value.

$\begin{matrix}\left. \begin{matrix}{{W(x)} = {{d/c} \times {x}}} & \left( {{{When}\mspace{14mu} 0} \leq {x} < c} \right) \\{{W(x)} = {{e \times {x}} + \left( {d - {e \times c}} \right)}} & \left( {{{When}\mspace{14mu} c} \leq {x}} \right)\end{matrix} \right\} & (8)\end{matrix}$

The intra-region correlation calculation unit 160 calculates thecorrelativity of each video signal within the left- and right-eye videoregions. For an intra-region correlation C for the whole video, eitherof an intra-region correlation value CL obtained in the left-eye videoregion and an intra-region correlation value CR obtained in theright-eye video region may be used, or the intra-region correlation Cmay be obtained from the average of CL and CR as shown in the followingformula (9).

C=(CL+CR)/2  (9)

Herein, the intra-region correlation CL in the left-eye video region andthe intra-region correlation value CR in the right-eye video region canbe respectively obtained according to the following formulas (10) and(11).

$\begin{matrix}{{CL} = {\sum\limits_{p = 0}^{{M/2} - 1}\; {\sum\limits_{q = 0}^{N - 1}\; {{{L\left( {p,q} \right)} - {L\left( {{p + {M/2}},q} \right)}}}}}} & (10) \\{{CR} = {\sum\limits_{p = 0}^{{M/2} - 1}\; {\sum\limits_{q = 0}^{N - 1}{{{R\left( {p,q} \right)} - {R\left( {{p + {M/2}},q} \right)}}}}}} & (11)\end{matrix}$

The evaluation value calculation unit 170 calculates an evaluation valueZ by obtaining the ratio of the correlation value S between the left-and right-eye video regions obtained by the cumulative difference valuecalculation unit 150 to the intra-region correlation C in the left- andthe right-eye video regions obtained by the intra-region correlationcalculation unit 160 according to the following formula (12).

Z=S/C  (12)

The determination unit 180 determines whether the input video is of athree-dimensional video signal in the side-by-side format, or the like,or a two-dimensional video signal based on the computed evaluation valueZ. When the input video is of a three-dimensional video format, thecorrelativity of the left-eye video region and the right-eye videoregion in the input video increases. In this case, since the correlationvalue S between the regions shown in the above formula (7) becomessmall, the evaluation value shown in the above formula (12) decreases.Thus, the determination unit 180 can determine that the input video isof a three-dimensional video format if the evaluation value Z outputfrom the evaluation value calculation unit 170 is low.

FIG. 7 shows a process of the determination unit 180 for determining avideo format of the input video based on the evaluation value Z in theform of a flowchart. The determination unit 180 is set to show adetermination result as a value of D (a value of D or 0:three-dimensional video, 1: determination deferred).

The determination unit 180 first checks whether the intra-regioncorrelation C computed by the intra-region correlation calculation unit160 is equal to or higher than a predetermined threshold value th_c(Step S701).

At this moment, when the intra-region correlation C is less than thepredetermined threshold value th_c (Yes in Step S701), the determinationresult D is output as 1, in other words, determination is deferred (StepS702). When the intra-region correlation C has a value close to 0, thereason is that there is a high possibility that the entire screen isflat, and thus there is not sufficient information for determining avideo format.

On the other hand, when the intra-region correlation C is equal to orhigher than the threshold value th_c (No in Step S701), sufficientinformation for determining a video format can be obtained from theinput video, and thus determination of a video formation is attemptedbased on the evaluation value Z computed by the evaluation valuecalculation unit 170 (Step S703).

In the present embodiment, two threshold values of th_a and th_b areused in the determination process of a video format based on theevaluation value Z (wherein, th_a<th_b). FIG. 8 graphically explains adetermination processing method of a video format based on theevaluation value Z.

If the evaluation value Z is low, the input video can be determined tobe in a three-dimensional video format (as described above). Thus, whenthe evaluation value Z is smaller than the threshold value th_a, thedetermination unit 180 determines that the input video isthree-dimensional video, and outputs 0 as the determination result D. Onthe other hand, when the evaluation value Z is equal to or greater thanthe threshold value th_b, the determination unit 180 determines that theinput video is two-dimensional video, and outputs 2 as the determinationresult D. In addition, when the evaluation value Z is equal to orgreater than th_a and smaller than th_b, the determination unit 180defers determination, and outputs 1 as the determination result D.

Note that the threshold values th_a and th_b are determined to bevalues, for example, 0.2 and 0.4, or the like. In addition,determination of the evaluation value Z may be performed using positionsof formulas having three or more stages (for example, 10 stages) ratherthan threshold values of two stages as shown in FIG. 8 so thatreliability for the determination values is expressed in stages.

When a still image in the side-by-side format is desired to bedetermined in the video format determination device 100, a “side-by-sidedetermination mode” is set as a determination mode. When thedetermination result D obtained from the video format determinationdevice 100 is 0, which is for three-dimensional video, the image isdetermined to be in the side-by-side format, and when the result is 2,which is for two-dimensional video, the image is determined to betwo-dimensional video. In addition, when the determination result D is1, which is for deferment of determination, the image is determined tobe two-dimensional video because there is also a possibility oferroneous determination.

In addition, when a still image in the top-and-bottom format is desiredto be determined in the video format determination device 100, a“top-and-bottom determination mode” is set as a determination mode. Whenthe determination result D obtained from the video format determinationdevice 100 is 0, which is for three-dimensional video, the image isdetermined to be in the top-and-bottom format, and when the result is 2,which is for two-dimensional video, the image is determined to betwo-dimensional video. In addition, when the determination result D is1, which is for deferment of determination, the image is determined tobe two-dimensional video because there is also a possibility oferroneous determination.

In addition, when there is no knowledge of whether the input video is ofa three-dimensional video signal in either of the side-by-side format orthe top-and-bottom format, or of a two-dimensional video signal, it isnecessary for the video format determination device 100 to determinesuch a plurality of video formats.

FIG. 9 shows a process of the determination unit 180 for determining theplurality of video formats based on the evaluation value Z in the formof a flowchart.

First, by setting the determination mode to be the side-by-side (SBS)determination mode, a determination process is performed, and thedetermination result D is obtained (Step S901).

Herein, when the obtained determination result D is 0 (Yes in StepS902), a final determination result E=SBS which indicates that theformat of the input video is the side-by-side format is output (StepS903), and then this process routine ends.

In addition, when the obtained determination result D is not 0 (No inStep S902), the determination mode is subsequently switched to thetop-and-bottom (TAB) determination mode, the determination process isperformed, and then the determination result D is obtained again (StepS904).

Herein, when the obtained determination result D is 0 (Yes in StepS905), a final determination result E=TAB which indicates that theformat of the input video is the top-and-bottom format is output (StepS906), and then this process routine ends.

In addition, when the obtained determination result D is not 0 (No inStep S905), it is checked whether or not the determination result D is 1(Step S907). Then, when D is 1 (Yes in Step S907), a final determinationresult E=HOLD which indicates that the determination is deferred isoutput (Step S908), and when D is not 1 (No in Step S907), a finaldetermination result E=2D which indicates that the input video is in thetwo-dimensional video format is output (Step S909), and the processroutine ends.

As described above, the display device 2000 mounted with the videoformat determination device 100 switches display formats of input videobased on determination results of video formats. Herein, in thedetermination methods as shown in FIGS. 7 to 9, there is a possibilitythat determination results are switched for each frame. When input videois a moving image, if determination results change in a short period oftime, display formats output on the screen of the display device 200change very often, and thus there is concern that such changes causeviewers displeasure. Therefore, it is necessary to stabilize theintervals of determination results output from the video formatdetermination device 100.

FIG. 10 shows a state transition diagram used in operation controlduring video format determination of a moving image by the video formatdetermination device 100. In the example shown, the video formatdetermination device 100 has three kinds of states which are an “SBSstate” in which input video is determined as three-dimensional video inthe side-by-side format, a “TAB state” in which the video is determinedas three-dimensional video in the top-and-bottom format, and a “2Dstate” in which the video is determined as two-dimensional video. Inaddition, the determination unit 180 determines state transition basedon a determination result (E) of a current frame, a determination state(T) of the previous frame thereof, and a time elapsed (CNT) after thedetermination result is changed. Each state in the drawing is outputfrom the video format determination device 100 as a final determinationresult of each video format. The initial state is set to be, forexample, the 2D state.

In the 2D state, if the determination result of the current frame ismaintained to be 2D, the state returns to the 2D state. On the otherhand, if the determination result of the current frame is change to SBSand a predetermined period of time elapses (in other words, if thedetermination result is SBS over several consecutive frames), the stateis transitioned from the 2D state to SBS. In addition, if thedetermination result of the current frame is changed to TAB and apredetermined period of time elapses, the state is transitioned from the2D state to TAB.

In addition, in the SBS state, if the determination result of thecurrent frame is maintained to be SBS, the state returns to the SBSstate. On the other hand, if the determination result of the currentframe is changed to TAB and a predetermined period of time elapses, thestate is transitioned from the SBS state to the TAB state. In addition,if the determination result of the current frame is changed to 2D and apredetermined period of time elapses, the state is transitioned from theSBS state to the 2D state.

In addition, in the TAB state, if the determination result of thecurrent frame is maintained to be TAB, the state returns to the TABstate. On the other hand, if the determination result of the currentframe is changed to 2D and a predetermined period of time elapses, thestate is transitioned from the TAB state to the 2D state. In addition,if the determination result of the current frame is changed to SBS and apredetermined period of time elapses, the state is transitioned from theTAB state to the SBS state.

FIG. 11 shows a process of the determination unit 180 to determinewhether or not transition should be performed between states in thestate transition diagram shown in FIG. 10 in the form of a flowchart.

First, the determination unit 180 sets different determination thresholdvalues in each state according to a state Tin a previous frame (StepS1101).

In the 2D state, for example, determination threshold values thatfacilitate detection of two-dimensional video such as th_a=0.15 andth_b=0.3 are set so that transition from detection of thetwo-dimensional video does not frequently occur. In addition, in thecase of a three-dimensional video state such as the SBS state or the TABstate, determination threshold values that facilitate detection ofthree-dimensional video such as th_a=0.25 and th_b=0.45 are set so thattransition from detection of the three-dimensional video does notfrequently occur.

When a determination result is ambiguous, the determination unit 180 ismade to respond only when video in a clearly different format is inputwithout allowing the determination state T to be transitioned, bysuppressing the frequency of transition from each state by thedetermination unit 180 in this manner, and accordingly, the intervals ofdetermination results can be stabilized.

Herein the determination unit 180 retains E for a variable F as theprevious determination result (previous frame) before performingdetermination of a plurality of video formats (Step S1102). Note that,at this moment, when E means HOLD (determination deferred), the value ofthe variable F is not updated. With this operation, E is not substitutedfor a previous determination result F. The initial value of E is set tobe the same value as T.

Then, the determination unit 180 executes a determination process forthe plurality of video formats according to the process shown in FIG. 9,and then obtains the determination result E for the current frame (StepS1103).

Next, the determination unit 180 checks whether or not the determinationresult E of the current frame is HOLD (determination deferred) (StepS1104).

Herein, when the determination result E of the current frame is HOLD(determination deferred) (Yes in Step S1104), the process routine endswithout updating either of the state T and a counter CNT that measuresthe time elapsed from detection of a change in the state.

On the other hand, when the determination result E of the current frameis not HOLD (determination deferred) (No in Step S1104), it is furtherchecked whether the determination result E of the current frame isdifferent from the current state T and the same as the previousdetermination result F (Step S1105).

When the determination result E of the current frame is different fromthe current state T and the same as the previous determination result F(Step S1105), the counter CNT that measures the elapsed time counts upvalues (Step S1106).

Then, when a value of the counter CNT that measures the elapsed timeexceeds a predetermined threshold value (change time) th_d (Yes in StepS1107), the current state T is updated to the determination result E ofthe current frame, and the counter CNT is reset so as to have the valueof 0 (Step S1108), and the process routine ends.

In addition, when the determination result E of the current frame is thesame as the current state T, or different from the previousdetermination result F (No in Step S1105), the changed determinationresult is not stabilized, and thus the counter CNT that measures theelapsed time is reset so as to have the value of 0 (Step S1109), andthen the process routine ends.

With the process shown in FIG. 11, the determination unit 180 obtains adetermination result different from a current state, and when thedifferent determination result is continued for a given time or longer,the state is transitioned to a new state as a determination result of avideo format, and accordingly, stabilized determination of a videoformat can be performed. As a result, the display device 2000 can stablydisplay a moving image according to the determination result.

The characteristics of the video format determination device 100 shownin FIG. 1 are summarized as follows.

(1) The region representative value calculation unit 120 converts aninput video signal of high resolution into representative values offeature amounts for every small region. Accordingly, formatdetermination that is hardly affected by parallax, bands of videosignals, and noise can be performed. In addition, by performingconversion into representative values of feature amounts of every smallregion, format determination can be performed with a small calculationamount.

(2) The correction value calculation unit 130 computes a correctionvalue based on an average value of feature amounts computed for eachregion, and the data correction unit 140 corrects the representativevalues of each region using this correction value, and thus, when thecorrelation between the left- and right-eye video regions is calculatedin the latter stage, influence of contrast, γ, and color can besuppressed.

(3) Since the intra-region correlation calculation unit 160 calculatesintra-region correlation between the left- and right-eye video regionsand the evaluation value calculation unit 170 computes a determinationvalue from the ratio of the inter-region correlation value to theintra-region correlation value at the same time as calculation of thecorrelation between the regions, format determination that is hardlyaffected by contrast, γ, and color can be performed. In addition, sincethere is little influence of two-dimensional video (refer to FIG. 28)having a high correlation between the left and right sides, performanceof discriminating two-dimensional video from three-dimensional video canbe enhanced.

(4) During the calculation of the correlation between the left- andright-eye video regions, the cumulative difference value calculationunit 150 uses a weighting function. Accordingly, by suppressing theinfluence of parallax, bands of video signals, and noise, determinationaccuracy of three-dimensional video improves.

(5) The determination unit 180 determines a format of input video usinga determination value computed based on an evaluation value of thecorrelation between the regions, but by providing deferment ofdetermination in determination of a three-dimensional video format and atwo-dimensional video format, the risk of erroneous determination can belowered.

(6) By changing a method of dividing and processing the left- andright-eye video regions, the video format determination device 100 canbe applied to determination of a plurality of differentthree-dimensional video formats, beginning from the side-by-side formatand the top-and-bottom format.

(7) In addition, by switching a plurality of determination modes andconsecutively executing determination processes, the video formatdetermination device 100 can simultaneously determine a plurality ofthree-dimensional video formats.

(8) When the video formation of a moving image is determined, the videoformat determination device 100 sets transition of determination resultsnot to frequently occur, or easily determines a desired video format bysetting determination threshold values according to a previousdetermination value.

(9) When the video formation of a moving image is determined, the videoformat determination device 100 can stabilize the intervals ofdetermination results with reference to the history of the determinationresults.

FIG. 12 shows another configuration example of a video formatdetermination device 1200 which can be applied to determination of aninput video format in the video signal processing unit 2001.

The video format determination device 1200 includes a feature amountcalculation unit 1210, a region representative value calculation unit1220, a luminance ranking calculation unit 1230, a luminance directioncalculation unit 1240, an evaluation value calculation unit 1250, and adetermination unit 1260. A video signal input to the video formatdetermination device 1200 is, for example, an HD signal of 60 Hz havinga pixel size of 1920×1080, a video signal having resolution of an SDsignal having a pixel size of 720×480, or a still image signal recordedby a digital camera. In the case of a video signal, a video formatthereof can be determined by processing one frame out of a moving imageof which frames are consecutively input.

The feature amount calculation unit 1210 calculates feature amounts whenthe video format of input video is determined. Hereinafter, luminancevalues of input video are set to be used as feature amounts.

The region representative value calculation unit 1220 divides a left-eyevideo region and a right-eye video region in a video frame respectivelyinto a plurality of small regions according to a determination modeinstructed from outside of the video format determination device 1200automatically or manually by a user, and computes a representative valueof feature amounts calculated by the feature amount calculation unit1210 for each small region. Herein, an average value of the featureamounts (luminance values) of each region is calculated as arepresentative value.

When, for example, a determination mode in which three-dimensional videoin the side-by-side format is determined is set, the regionrepresentative value calculation unit 1220 divides input video into twohalves on the left and right sides, further divides the respective leftand right regions into M×N small regions (refer to FIG. 2), and thencomputes the average value of the small regions according to the aboveformulas (1) and (2). In addition, when a determination mode in whichthree-dimensional video in the top-and-bottom format is determined isset, the region representative value calculation unit 1220 divides inputvideo into two halves on the upper and lower sides, further divides therespective upper and lower regions into M×N small regions (refer to FIG.3), and then computes the average value of the small regions.

Note that, as methods for dividing input video, a method in whichcontracted regions of blocks obtained by dividing a left-eye videoregion and a right-eye video region so as to respectively have M rowsand N columns are used (refer to FIG. 4), and a method in which anoverlapping region with adjacent blocks is used (refer to FIG. 5) areexemplified, in addition to the method in which the regions are clearlydivided into blocks as shown in FIGS. 2 and 3.

In addition, the number of divisions within the range not affected byparallax is also a characteristic of the technology disclosed in thepresent specification. In other words, in the examples shown in FIGS. 2and 3, the number of M×N divisions is set to 4×4 divisions respectivelyfor the left-eye video region and the right-eye video region, but asufficiently rough number such as 16×16 divisions, 12×12 divisions, or8×8 divisions is another characteristic thereof. The number of divisionsthat is asymmetric in the horizontal direction and the verticaldirection such as 16×8 divisions may be used. In this manner, by using asufficiently rough number of divisions for input video, the influence ofnoise or bands of video signals as well as the influence of parallax canbe eliminated, and at the same time, a calculation amount can bereduced.

The luminance ranking calculation unit 1230 ranks the small regions ineach row respectively for the left-eye display region on the left halfof a video frame and the right-eye display region on the right halfthereof based on the representative value of each small region, that isaverage luminance computed by the region representative valuecalculation unit 1220. For example, it is assumed that input video isthree-dimensional video in the side-by-side format shown in FIG. 13 andresults obtained by computing representative values for each smallregion of the video using the region representative value calculationunit 1220 are as shown in FIG. 14. In this case, if ranking of smallregions for each row in each of the left-eye display region and theright-eye display region is performed by the luminance rankingcalculation unit 1230, the results shown in FIG. 15 are obtained. Inaddition, when the input video is in the top-and-bottom format, theluminance ranking calculation unit 1230 ranks the small regions in eachcolumn in each of the left-eye display region on the upper half and theright-eye display region on the lower half of a video frame.

The luminance direction calculation unit 1240 calculates directions inwhich luminance changes in the small regions in each of the left-eyedisplay region and the right-eye display region in a video frame basedon the representative values of each small region, that is, the averageluminance computed in the region representative value calculation unit1220.

For example, the direction of luminance changes can be obtained forsmall regions at the center of 3×3 by multiplying a 3×3 weighting filtercoefficient for each small 3×3 region. As a weighting filter of thiskind, template matching of Prewitt (for example, refer to JapaneseUnexamined Patent Application Publication No. 2009-217606) is known. Inthis matching method, 8 kinds of masks respectively having values anddirections of masks as shown in FIG. 16 are used. Then, a product-sumoperation of each average luminance of a focused small area and 8peripheral small regions and the values of the masks is performed, and adirection indicated by a mask having a maximum value is set to serve asthe direction of a luminance change of the focused small region. If the8 masks shown in FIG. 16 are used, 8 directions of the luminance changesare obtained at every 45 degrees. If the template matching of Prewitt isapplied to three-dimensional video in the side-by-side format as shownin FIG. 13, the changes of luminance direction as shown in FIG. 17 canbe obtained.

The evaluation value calculation unit 1250 compares the results obtainedfrom ranking by the luminance ranking calculation unit 1230 forcorresponding small regions of the left-eye video region and theright-eye video region. Then, small regions of which the rankingscoincide on the left and right sides are set to have 1, those that donot coincide are set to have 0, and the number of regions R of which therankings coincide on the left and right sides is computed as anevaluation value for ranking. As the number of small regions of whichthe rankings coincide increases, in other words, as the value of Rbecomes large, input video can be determined to be three-dimensionalvideo. FIG. 18 shows evaluation results for the results of ranking ofluminance shown in FIG. 15. In the example of the drawing, since therankings of all 24 small regions coincide, the evaluation value R is 24.

In addition, the evaluation value calculation unit 1250 compares theresults obtained by calculating the directions of luminance changesusing the luminance direction calculation unit 1240 for correspondingsmall regions of the left-eye video region and the right-eye videoregion. Then, small regions of which the directions of the luminancechanges coincide on the left and right sides are set to have 1, thosethat do not coincide are set to have 0, and the number of regions P ofwhich the directions of the luminance changes coincide on the left andright sides is computed as an evaluation value for a direction of aluminance change. If the 8 masks shown in FIG. 16 are used, 8 directionsof the luminance changes are obtained at every 45 degrees. When thedetermination criterion is alleviated, an allowable range of a directionof a luminance change on the left and right sides (for example, −45degrees, 0 degrees, and 45 degrees are assumed to coincide with eachother), and a region that belongs to the range is obtained. As thenumber of small regions in which the directions of luminance changescoincide increases, in other words, as the value of P becomes large,input video can be determined to be three-dimensional video. FIG. 19shows evaluation results for the calculation results of the directionsof the luminance changes shown in FIG. 17. In the example of thedrawing, since the rankings of 22 out of 24 small regions coincide, theevaluation value P is 22.

For example, the determination unit 1260 provides three-dimensionalvideo determination threshold values th_R_3D and th_P_3D, andtwo-dimensional video determination threshold values th_R_2D and th_P_2Dfor each of the evaluation values R and P. Then, since the degree ofsimilarity of the left- and right-eye video regions increases as theevaluation values become higher, there is a possibility ofthree-dimensional video. Conversely, since the degree of similarity ofthe left- and right-eye video regions decreases as the evaluation valuesbecome lower, there is a possibility of two-dimensional video. Inaddition, when a video is not determined to be three-dimensional videoor two-dimensional video due to an intermediate degree of similarity,the determination unit 1260 defers determination. Specifically, based onthe rankings of luminance and directions of luminance changes,determination can be made using the following respective formulas (12)and (13).

$\begin{matrix}{{{Determination}\mspace{14mu} {based}\mspace{14mu} {on}\mspace{14mu} {rankings}\mspace{14mu} {of}\mspace{14mu} {luminance}}\begin{matrix}{R \geq {{TH\_ R}\_ 3D}} & {{{Determined}}\mspace{14mu} {to}\mspace{14mu} {be}\mspace{14mu} {three}\text{-}{dimensional}\mspace{14mu} {video}} \\{{{TH\_ R}\_ 3D} > R > {{TH\_ R}\_ 2D}} & {{{Determination}}\mspace{14mu} {deferred}} \\{{{TH\_ R}\_ 2D} \geq R} & {{{Determined}}\mspace{14mu} {to}\mspace{14mu} {be}\mspace{14mu} {two}\text{-}{dimensional}\mspace{14mu} {video}}\end{matrix}} & (13) \\{{{Determination}\mspace{14mu} {based}\mspace{14mu} {on}\mspace{14mu} {directions}\mspace{14mu} {of}\mspace{14mu} {luminance}\mspace{14mu} {changes}}\begin{matrix}{P \geq {{TH\_ P}\_ 3D}} & {{{Determined}}\mspace{14mu} {to}\mspace{14mu} {be}\mspace{14mu} {three}\text{-}{dimensional}\mspace{14mu} {video}} \\{{{TH\_ P}\_ 3D} > P > {{TH\_ P}\_ 2D}} & {{{Determination}}\mspace{14mu} {deferred}} \\{{{TH\_ P}\_ 2D} \geq P} & {{{Determined}}\mspace{14mu} {to}\mspace{14mu} {be}\mspace{14mu} {two}\text{-}{dimensional}\mspace{14mu} {video}}\end{matrix}} & (14)\end{matrix}$

The determination unit 1260 can determine the format of input video withreference to either or both of the evaluation values R and P calculatedby the evaluation value calculation unit based on calculation results bythe luminance ranking calculation unit 1230 and the luminance directioncalculation unit 1240.

In addition, since the above determination is executed in units of oneinput frame, there is a possibility of the determination result changingin units of one frame due to changes and noise of an image in the caseof a moving image. If the determination result changes in a short periodof time, display formats output by the display device 2000 on the screenthereof change too often, and thus there is concern of such changescausing viewers displeasure. Thus, it is necessary to stabilize theintervals of the determination results output from the video formatdetermination device 1200. Therefore, using the following methods, thedetermination unit 1260 may suppress determination changes in timedirections.

(1) When the same determination result is obtained N consecutive times(for N frames), the determination is confirmed.

(2) M or more determination results out of the N consecutivedeterminations (for N frames) are adopted.

In addition, when there is no determination result that satisfies thecondition (1) or (2), an input video cannot be determined to bethree-dimensional video or two-dimensional video, and thus thedetermination unit 1260 may output a result of “determination deferred”.

The characteristics of the video format determination device 100 shownin FIG. 1 are summarized below.

(1) Since determination is made without considering absolute values ofluminance in the left- and right-eye video regions, a video format canbe accurately determined even for a three-dimensional video image ofwhich luminance significantly deviates in the left- and right-eye videoregions.

(2) The left- and right-eye video regions are respectively divided intosmall regions, and evaluation is performed using a representative valueof average luminance values, or the like for each region. Accordingly,frame determination is hardly affected by parallax, bands of videosignals, and noise.

(3) The left- and right-eye video regions are respectively divided intosmall regions, and evaluation is performed using a representative valueof average luminance values, or the like for each region. Thus, acalculation amount may be small in comparison to a method in whichevaluation is performed in a unit of pixels.

(4) The video format determination device 1200 can be applied todetermination of a plurality of different three-dimensional videoformats beginning from the side-by-side format and the top-and-bottomformat by changing a method of dividing and processing left- andright-eye video regions.

Additionally, the present technology may also be configured as below.

(1) A video format determination device including:

a video input unit that receives video having a feature amount for eachpixel;

a region representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region;

a correction value calculation unit that calculates a correction valueto correct the representative values based on an average value offeature amounts of the left-eye video region and an average value offeature amounts of the right-eye video region;

a data correction unit that corrects the representative values of therespective small regions computed for one of the left-eye video regionand the right-eye video regions using the correction value;

an inter-region correlation calculation unit that calculates thecorrelation between the left- and right-eye video regions bycumulatively adding differences of the representative values ofcorresponding small regions in the left-eye video region and theright-eye video region; and

an evaluation determination unit that evaluates the correlation betweenthe left- and right-eye video regions to determine whether input videois in the three-dimensional video format.

(2) A video format determination device including:

a video input unit that receives video having a feature amount for eachpixel;

a region representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region;

an inter-region correlation calculation unit that calculates thecorrelation between the left- and right-eye video regions bycumulatively adding differences of the representative values ofcorresponding small regions in the left-eye video region and theright-eye video region;

an intra-region correlation calculation unit that calculates thecorrelation within at least one region of the left-eye video region andthe right-eye video region; and

an evaluation determination unit that calculates an evaluation valuebased on a ratio of the correlation between the left- and right-eyevideo regions to the correlation within the region to determine whetherinput video is in the three-dimensional video format based on theevaluation value.

(3) The video format determination device according to (1), wherein theregion representative value calculation unit uses a luminance signal ofeach pixel as a feature amount.

(4) The video format determination device according to (1) or (2),wherein the inter-region correlation calculation unit calculates thecorrelation between the left- and right-eye video regions based on thedifferences of the representative values of corresponding small regionsin the left-eye video region and the right-eye video region.

(5) The video format determination device according to (1) or (2),wherein the inter-region correlation calculation unit calculates thecorrelation between the left- and right-eye video regions by performingcumulative weighted addition of the differences of the representativevalues of corresponding small regions between the left-eye video regionand the right-eye video region.

(6) The video format determination device according to (5), wherein theinter-region correlation calculation unit performs the cumulativeweighted addition using a weighting function that suppresses addition ofa difference whose value is equal to or lower than a predeterminedvalue.

(7) The video format determination device according to (1), furtherincluding:

an intra-region correlation calculation unit that calculates thecorrelation within at least one region of the left-eye video region andthe right-eye video region,

wherein the evaluation determination unit calculates an evaluation valuebased on a ratio of the correlation between the left- and right-eyevideo regions to the correlation within the region to determine whetherinput video is in the three-dimensional video format based on theevaluation value.

(8) The video format determination device according to (2) or (7),wherein the evaluation determination unit defers determination of avideo format of input video when the correlation within the region has avalue equal to or lower than a predetermined threshold value.

(9) The video format determination device according to (1) or (2),wherein the region representative value calculation unit disposes theleft-eye video region and the right-eye video region on left and rightof the input video, respectively, and computes representative values ofthe respective small regions in a determination mode to determinewhether or not the input video is three-dimensional video in aside-by-side format.

(10) The video format determination device according to (1) or (2),wherein the region representative value calculation unit disposes theleft-eye video region and the right-eye video region on top and bottomof the input video, respectively, and computes representative values ofthe respective small regions in a determination mode to determinewhether or not the input video is three-dimensional video in atop-and-bottom format.

(11) The video format determination device according to (1) or (2),

wherein a plurality of determination modes in which a video format isdetermined with regard to each of a plurality of three-dimensional videoformats is provided, and

wherein, when input video is determined not to be three-dimensionalvideo in a certain determination mode, the evaluation determination unitdetermines whether or not the input video is three-dimensional video byswitching to another determination mode.

(12) The video format determination device according to (1) or (2),wherein, during determination of a video format of a moving image, theevaluation determination unit decides whether or not a determinationstate of a video format should be transitioned based on a determinationresult of a video format for a current frame, a determination state of avideo format for the previous frame, and a time elapsed from a change inthe determination result.

(13) The video format determination device according to (12), whereinthe evaluation determination unit sets a threshold value to be used indetermining an evaluation value according to a determination state of avideo format.

(14) A video format determination device including:

a video input unit that receives video having a feature amount for eachpixel;

a region representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region;

a representative value ranking calculation unit that calculates rankingsof the small regions for each row and each column based on the computedrepresentative values in each of the left-eye video region and theright-eye video region; and

an evaluation determination unit that evaluates a degree of similarityof rankings of corresponding small regions between the left-eye videoregion and the right-eye video region to determine whether or not theinput video is in the three-dimensional video format.

(15) A video format determination device including:

a video input unit that receives video having a feature amount for eachpixel;

a region representative value calculation unit that divides a left-eyevideo region and a right-eye video region in a three-dimensional videoformat to be determined in input video into small regions having M rowsand N columns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region;

a representative value direction calculation unit that calculatesdirections in which the representative values change in each of thesmall regions in each of the left-eye video region and the right-eyevideo region; and

an evaluation determination unit that further evaluates a degree ofsimilarity of directions in which the representative values change incorresponding small regions in the left-eye video region and theright-eye video region to determine whether or not the input video is inthe three-dimensional video format.

(16) The video format determination device according to (15), wherein,by multiplying a weighting filter coefficient of n m by each of n msmall regions in each of the left-eye video region and the right-eyevideo region, the representative value direction calculation unitcalculates the directions in which the representative values change ineach of the small regions.

(17) A video format determination method including:

receiving video having a feature amount for each pixel;

dividing a left-eye video region and a right-eye video region in athree-dimensional video format to be determined in input video intosmall regions having M rows and N columns, respectively, and thencomputing representative values of feature amounts of the respectivesmall regions for each of the left-eye video region and the right-eyevideo region;

calculating a correction value to correct the representative valuesbased on an average value of feature amounts of the left-eye videoregion and an average value of feature amounts of the right-eye videoregion;

correcting the representative values of the respective small regionscomputed for one of the left-eye video region and the right-eye videoregions using the correction value;

calculating the correlation between the left- and right-eye videoregions by cumulatively adding differences of the representative valuesof corresponding small regions in the left-eye video region and theright-eye video region; and

evaluating the correlation between the left- and right-eye video regionsto determine whether input video is in the three-dimensional videoformat.

(18) A video format determination method including:

receiving video having a feature amount for each pixel;

dividing a left-eye video region and a right-eye video region in athree-dimensional video format to be determined in input video intosmall regions having M rows and N columns, respectively, and thencomputing representative values of feature amounts of the respectivesmall regions for each of the left-eye video region and the right-eyevideo region;

calculating the correlation between the left- and right-eye videoregions by cumulatively adding differences of the representative valuesof corresponding small regions in the left-eye video region and theright-eye video region;

a. calculating the correlation within at least one region of theleft-eye video region and the right-eye video region; and

calculating an evaluation value based on a ratio of the correlationbetween the left- and right-eye video regions to the correlation withinthe region to determine whether input video is in the three-dimensionalvideo format based on the evaluation value.

(19) A video format determination method including:

receiving video having a feature amount for each pixel;

dividing a left-eye video region and a right-eye video region in athree-dimensional video format to be determined in input video intosmall regions having M rows and N columns, respectively, and thencomputing representative values of feature amounts of the respectivesmall regions for each of the left-eye video region and the right-eyevideo region;

calculating rankings of the small regions for each row and each columnbased on the computed representative values in each of the left-eyevideo region and the right-eye video region; and

evaluating a degree of similarity of rankings of corresponding smallregions between the left-eye video region and the right-eye video regionto determine whether or not the input video is in the three-dimensionalvideo format.

(20) A video format determination method including:

receiving video having a feature amount for each pixel;

dividing a left-eye video region and a right-eye video region in athree-dimensional video format to be determined in input video intosmall regions having M rows and N columns, respectively, and thencomputing representative values of feature amounts of the respectivesmall regions for each of the left-eye video region and the right-eyevideo region;

calculating directions in which the representative values change in eachof the small regions in each of the left-eye video region and theright-eye video region; and

evaluating a degree of similarity of directions in which therepresentative values change in corresponding small regions in theleft-eye video region and the right-eye video region to determinewhether or not the input video is in the three-dimensional video format.

(21) A display device including:

an input unit that receives video signals;

a video signal processing unit that determines the format of input videosignals, and performs processing of a three-dimensional video signal ora two-dimensional video signal by switching display formats according tothe determination result; and

a display unit that displays video signals that have been processed inthe video signal processing unit on a screen,

wherein the video signal processing unit divides a left-eye video regionand a right-eye video region in a three-dimensional video format to bedetermined in input video into small regions having M rows and Ncolumns, respectively, and then computes representative values offeature amounts of the respective small regions for each of the left-eyevideo region and the right-eye video region, calculates a correctionvalue to correct the representative values based on an average value offeature amounts of the left-eye video region and an average value offeature amounts of the right-eye video region, calculates a correctionvalue to correct the representative values based on an average value offeature amounts of the left-eye video region and an average value offeature amounts of the right-eye video region using the correctionvalue, calculates the correlation between the left- and right-eye videoregions by cumulatively adding differences of the representative valuesof corresponding small regions in the left-eye video region and theright-eye video region, and evaluates the correlation between the left-and right-eye video regions to determine whether input video is in thethree-dimensional video format.

Hereinabove, the technology disclosed in the present specification hasbeen described in detail with reference to a specific embodiment.However, it should be understood by those skilled in the art thatvarious modifications, combinations, sub-combinations and alterationsmay occur depending on design requirements and other factors insofar asthey are within the scope of the appended claims or the equivalentsthereof

In the present specification, description has been provided focusing onan embodiment in which a three-dimensional video format such as theside-by-side format and the top-and-bottom format in which left andright videos are transmitted as one frame is determined, but theapplication range of the technology disclosed in the presentspecification is not limited to any specific three-dimensional videoformat. For example, in a case of the frame sequential scheme in whichleft-eye video and right-eye video are alternately transmitted for eachframe, the technology disclosed in the present specification can berealized in the same manner by performing calculation of the correlationbetween regions and calculation of intra-region correlation.

In addition, the technology disclosed in the present specification canbe applied not only to a three-dimensional video display format usingactive glasses such as the shutter glasses as described above but alsoto a three-dimensional video display format using passive glasses and athree-dimensional video display format for the naked eye.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A video format determination device comprising: avideo input unit configured to receive at least one video having afeature amount for each pixel; a region representative value calculationunit configured to divide a left-eye video region and a right-eye videoregion in a three-dimensional video format to be determined in inputvideo into a plurality of blocks having M rows and N columns,respectively, and compute representative values of feature amounts ofthe respective plurality of blocks for each of the left-eye video regionand the right-eye video region; a correction value calculation unitconfigured to calculate a correction value to correct the representativevalues based on an average value of the feature amounts of the left-eyevideo region and an average value of the feature amounts of theright-eye video region; a data correction unit configured to correct therepresentative values of the respective plurality of blocks computed forone of the left-eye video region and the right-eye video region usingthe correction value; an inter-region correlation calculation unitconfigured to calculate the correlation between the left-eye videoregion and the right-eye video region by cumulatively adding differencesof the representative values of the corresponding plurality of blocks inthe left-eye video region and the right-eye video region; and anevaluation determination unit configured to evaluate the correlationbetween the left-eye video region and the right-eye video region todetermine whether the input video is in the three-dimensional videoformat or a two-dimensional video format.
 2. The video formatdetermination device according to claim 1, wherein the regionrepresentative value calculation unit is configured to use a luminancesignal of each pixel as the feature amount.
 3. The video formatdetermination device according to claim 1, wherein the inter-regioncorrelation calculation unit is configured to calculate the correlationbetween the left-eye video region and the right-eye video region basedon the differences of the representative values of the correspondingplurality of blocks in the left-eye video region and the right-eye videoregion.
 4. The video format determination device according to claim 1,wherein the inter-region correlation calculation unit is configured tocalculate the correlation between the left-eye video region and theright-eye video region by performing cumulative weighted addition of thedifferences of the representative values of the corresponding pluralityof blocks between the left-eye video region and the right-eye videoregion.
 5. The video format determination device according to claim 4,wherein the inter-region correlation calculation unit is configured toperform the cumulative weighted addition using a weighting function thatsuppresses addition of a difference whose value is equal to or lowerthan a predetermined value.
 6. The video format determination deviceaccording to claim 1, further comprising: an intra-region correlationcalculation unit configured to calculate the correlation within at leastone region of the left-eye video region and the right-eye video region,wherein the evaluation determination unit is configured to calculate anevaluation value based on a ratio of the correlation between theleft-eye video region and the right-eye video region to the correlationwithin the region to determine whether the input video is in thethree-dimensional video format or the two-dimensional video format basedon the evaluation value.
 7. The video format determination deviceaccording to claim 6, wherein the evaluation determination unit isconfigured to defer determination of a video format of the input videowhen the correlation within at least one region of the left-eye videoregion and the right-eye video region has a value equal to or lower thana predetermined threshold value.
 8. The video format determinationdevice according to claim 1, wherein the region representative valuecalculation unit is configured to dispose the left-eye video region andthe right-eye video region on left and right of the input video,respectively, and compute the representative values of the respectiveplurality of blocks in a determination mode to determine whether or notthe input video is the three-dimensional video in a side-by-side format.9. The video format determination device according to claim 1, whereinthe region representative value calculation unit is configured todispose the left-eye video region and the right-eye video region on topand bottom of the input video, respectively, and compute therepresentative values of the respective plurality of blocks in adetermination mode to determine whether or not the input video is thethree-dimensional video in a top-and-bottom format.
 10. The video formatdetermination device according to claim 1, wherein a plurality ofdetermination modes in which a video format is determined with regard toeach of a plurality of three-dimensional video formats is provided, andwherein, in an event the input video is determined not to be athree-dimensional video in a certain determination mode, the evaluationdetermination unit is configured to determine whether or not the inputvideo is the three-dimensional video by switching to anotherdetermination mode.
 11. The video format determination device accordingto claim 1, wherein, during determination of a video format of a movingimage, the evaluation determination unit is configured to decide whetheror not a determination state of the video format should be transitionedbased on a determination result of the video format for a current frame,a determination state of the video format for the previous frame, and atime elapsed from a change in the determination result.
 12. The videoformat determination device according to claim 1, wherein the evaluationdetermination unit is configured to set a threshold value to be used indetermining an evaluation value according to a determination state of avideo format.
 13. A video format determination method comprising:receiving video having a feature amount for each pixel; dividing aleft-eye video region and a right-eye video region in athree-dimensional video format to be determined in input video into aplurality of blocks having M rows and N columns, respectively, andcomputing representative values of feature amounts of the respectiveplurality of blocks for each of the left-eye video region and theright-eye video region; calculating a correction value to correct therepresentative values based on an average value of the feature amountsof the left-eye video region and an average value of the feature amountsof the right-eye video region; correcting the representative values ofthe respective plurality of blocks computed for one of the left-eyevideo region and the right-eye video region using the correction value;calculating correlation between the left-eye video region and theright-eye video region by cumulatively adding differences of therepresentative values of the corresponding plurality of blocks in theleft-eye video region and the right-eye video region; and evaluating thecorrelation between the left-eye video region and the right-eye videoregion to determine whether the input video is in the three-dimensionalvideo format or a two-dimensional video format.
 14. A display devicecomprising: an input unit configured to receive at least one videosignal; a video signal processing unit configured to determine format ofthe input video signal, and perform processing of a three-dimensionalvideo signal or a two-dimensional video signal by switching displayformats according to determination result; and wherein the video signalprocessing unit is configured to divide a left-eye video region and aright-eye video region in a three-dimensional video format to bedetermined in the input video signal into plurality of blocks having Mrows and N columns, respectively, and compute representative values offeature amounts of the respective plurality of blocks for each of theleft-eye video region and the right-eye video region, calculate acorrection value to correct the representative values based on anaverage value of the feature amounts of the left-eye video region and anaverage value of the feature amounts of the right-eye video region,correct the representative values of the respective plurality of blockscomputed for one of the left-eye video region and the right-eye videoregion using the correction value, calculate correlation between theleft-eye video region and the right-eye video region by cumulativelyadding differences of the representative values of the correspondingplurality of blocks in the left-eye video region and the right-eye videoregion, and evaluate the correlation between the left-eye video regionand the right-eye video region to determine whether the input videosignal is in the three-dimensional video format or a two-dimensionalvideo format.